Deciphering molecular mechanism underlying antileishmanial activity of Nyctanthes arbortristis, an Indian medicinal plant

Nyctanthes arbortristis L. (Oleaceae) is widely used in the traditional medicine of India. The plant is shown to have antibacterial and antileishmanial activities. Evaluation of iridoid glucosides from the plant as inhibitor of trypanothione reductase (TryR), a validated drug target enzyme of the Leishmania parasite. The study contributes towards understanding mechanism of antileishmanial effect of the plant. TryR of Leishmania parasite is expressed and purified. Iridoid glucosides are isolated from the plant and tested as inhibitor of TryR enzyme of the parasite. Inhibitory constant (Ki) of various iridoid glucosides ranges from 3.24±0.05μM to 6.49±0.05μM. Thus, the molecular mechanism underlying antileishmanial activity of these compounds is mediated through inhibition of TryR. The current study also points out towards potential application of iridoid glucosides as novel drugs against the disease.